These are identifiable features on the Earth’s surface with known geographic coordinates. These locations serve as reference points for georeferencing remotely sensed data, such as aerial imagery or satellite imagery. For instance, a painted marker at a precise latitude, longitude, and elevation, visible in an aerial photograph, would be a representative example.
Their significance lies in their ability to correct geometric distortions inherent in remotely sensed data. This correction process ensures the accurate alignment of the data with a real-world coordinate system. The use of these reference locations results in measurements derived from the imagery being reliable and precise. Historically, surveying techniques were used to establish these locations; however, modern methods increasingly utilize GPS and other precise positioning technologies.
